JP2001-74154A discloses a relief valve capable of adjusting relief pressure.
In the above-mentioned relief valve, by changing a threaded depth of an adjusting screw that is threaded to a case, it is possible to change compression amount of a spring that is provided between a valve body and the adjusting screw, in other words, it is possible to change biasing force exerted on the valve body by the spring. With such a configuration, it is possible to adjust the relief pressure at which the valve body is separated from a valve seat.